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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0d3a41df8ad17f79dbd2b5ba9bd1a5d99a64f2d63ce2f49eae2dfbd9db21225' 
  AND token = 'fNbkyh3MJJ1AtFESqsBNja3BnBb8rxfKppQQcZu5zi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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