SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57c7b9ca0dde1f354489c1b3a7e82029c140611c3a6608f9be664b850c66af25' 
  AND token = 'HBoKeHif4jGPdSGTQ4EGbjqprV314whgC0ZfnBhxYD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}