SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '702eb8bce08e620d78aa182dabe946165432fdc2e7ecc5690f2ebb0e9fdd235e' 
  AND token = 'F68TC8rPXXcVH1gYoyGawolQVeFCGL0nMoZB9iKvdzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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