SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cf990169306dbe79f6f97bbb1f4fe14091e54cdd5f8e7eb79cd12d9f178b0e5' 
  AND token = '2yY0Yj/V2ZVj6hypLHHtpM8JvZuuVhfafu3oDuCc2NA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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