SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbaa9840b7523e9b8077a28416a661a42858084c865809d1bfcaeabfceac83dc' 
  AND token = 'bfsUuxXDp8Xq2dzpKkRBwlJNdAh1oROip+6BcsjzXbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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