SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcbadfb222185f4260ae1029cbdb17502237ab0ae2adf034be8d231a129dbc24' 
  AND token = 'gSejtiQrrHajV8cGzlo02K/6yDcuYGvankgNh8p23fA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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