SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a37391abcd1fc51817bf9bef6faf384b70912938a542702343cfca6f31b4f8b' 
  AND token = 'D5YfDQEWtkcBhQ90pUUrOaCcrC5xQ6LyCin9i8v30fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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