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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca7b1f2937d4c4fb1fcf293d9a876702c82861ac5cac069f7d02768787c4ae69' 
  AND token = 'rRUf7EaJYb7ltIrEMAY9NV6ShbtBLgtfqeSTOQLK4Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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