SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd983f265f11c9ad06bd99be0aea851085e51aaa2189ff83fb721b7d284b6749' 
  AND token = 'xkdVdtsmUEOpukWewz6ZCPGFJ66qkVI4xYHYJXLca5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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