SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c335b7c7cea27579f2562548446d55d181299b30be41e6e3de3ab66182879c3f' 
  AND token = 'YB+lQKPPS1O+inCtx2q6xN4JswVbvcXS1S2yo/CUg8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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