SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4053227529c1b8047c27047cf24d997962b248065889df2347287a186e1003e3' 
  AND token = 'OUMECmiGIAYCBZx67Rrjr2c/bCJHtzjh6IRiV5KRjWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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