SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ae69452c27d9221af39a45d4f348046437fe29bc7f3286d20463bcf8f3adbf' 
  AND token = 'LQPgS5h/JoyQnHz8f4dC2URjXXCtJuVkjkEvxmOktRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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