SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b975a8afd0ed1ef53037a69193125dc0489eaeefe799a273b3851d37b39a69a6' 
  AND token = 'LHpKU90Q1HpHuYKYD77a413CHTw0yeMomK+HbNUlUnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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