SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7cf417d7207061802d947eca608cb78c1a033ff5c842d106eafcf1b8aea7cfb' 
  AND token = 'un4RqTcPENG1JC5slAzFHcSAPxQAKfLxwwVAm4PJco0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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