SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e75da892604f1235bb548ab22b84ff9ec6892140a1d8da6968aaeba23156523' 
  AND token = 'YquvA3EAO+WtPjdxLlcOW2UAJrJH9ilZYEZl8KHzpZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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