SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd803efdf78e76672657f7975dea4691b61e0e58a4fd8a1294ddd6ce85fe63c65' 
  AND token = 'RIM3HDnM4sfE19SSsjaH9I+mBjBd1FjOUeMtH70XGXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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