SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c4123e3de1ea4375c773a31ad0ac0c2084cf6231d6438ba0d640a098e481136' 
  AND token = 'JaR86p/TMRg4Aj/TEBlo7P8DL5m5qjufgbmvYQXVE/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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