SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda143e494067ca530f89d18ffbdaa8347702b01e892ee83218d762d86c6b097' 
  AND token = 'USGrpYMmuPKOYMCnktYNfTU8Ll7nRHdCLgPPMwgS7sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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