SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b5dbab9018eb616a56626576aed9cda8cb98c492f3494667c83a7017bec8cb' 
  AND token = 'aAhuWYuENDwY0xZ5bMKT++GScIvzCZJ1GZUuPSYp6Xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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