SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1cde7d9204c795f4629ad83f189a008e4b5e15e98b64cd7e172f0b063c57ea3' 
  AND token = 'k4bUJkSy1UMXD9DmR3A3cGxiJvr4aEWeYoTMMlpThH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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