SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e978df7f294cdab840460a52d1c662f800eeda3348dc1250a9cdc9a92dd82e89' 
  AND token = 'nZyOM/hwP9gJInIOFAHQwBtLcStnbht/1Bantd8Bw34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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