SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '212a91e25cb56e1837ac00865f9a5e631f3455413879a85d6e95d376ec41e42f' 
  AND token = 'wobTSD42FXJv3K2+EgLhRus+2Y0buvPpj1pSQ7+I8/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}