SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74547ccc4c865afa038490cfd434a08ff34615672ff2b32899e33198a40a90af' 
  AND token = '0+TIrDj4jVe/g1XnnyajdUtsjB/a/MlxnTFbvPn/i94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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