SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020871990d419add591a5254b98ee59c1cf31814f6225fb0ab651d74adb4df5a' 
  AND token = 'trSQOr/7D5tX1UnJk9ocnbZsjuL5zfGMr5eHB0Gq7vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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