SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffcb6d8e97985202fcc9b06ac3404750d0d11ac3be4309a22170f1435bdd241b' 
  AND token = 'gX8QPiIDFzzzyohxr9e5cBo882TBcxt6kUShW12nC30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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