SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8749e0ea1cb0ae197d5d282919ed5cbba49e4223ca8177d562aa593d91725e1b' 
  AND token = 'NkfLjW43PmIrQ1AUtTSZU0W2i0/YF5ffe9YMQJ2RlNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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