SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44fc525cf4d571b500dd875ab32e76984681609139cad0a6a644f7ce5729688b' 
  AND token = '+gNJjPgffg+XFp+PVy+LJf3v2rd+uN28zoDu7vBOfkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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