SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4edd447b3e6714c0e6a89dddbf6680f41624ec3b5c3d5877fda28fdffd2c1d18' 
  AND token = '77KUEOVKTtcQLMpYnLoSa8qaI5tMh6VbfEqPRLJU8zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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