SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9a22af943de5c69323a04b08459a2f81e8c3de107ab1ecc9b4651543c6a0d9' 
  AND token = '40O1L5bI9rgtYQueInjmTzAh0mjLzY7MOZcVyhWrfak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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