SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48112fa7aa6d1392264e40f8a4b91760d97c8d04d0bd7b340f8cadba33c662f6' 
  AND token = '7VUkoE/ljqYCM9SWIZXpDKxvW0oFIHE+RNmFqwQy3r8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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