SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00bfd523cfc25198000ebc6a13ae6115912bf6f23ad3403707f9fa9010321add' 
  AND token = 'teGdjh6DAs2UOfYTMt7otLsAgmUNIT1uJCFhWLnCQnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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