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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6fbb8d07b2f20f5cdd3843e1571f63c4b2fe9c09474e72f1b391255fa13b9a1' 
  AND token = '6pCX0rj7NyUdt9WUdyMDfvq1jgton2oPmmIYkwb4Rco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}