SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfdc709197bcf47f6a4fe1d90c765dcf56c1a2a4e2dab5f97f9e5c31d4606b55' 
  AND token = 'FnVcyahSME1HxoI1awsfED6LgOe91i8vFe4V2NpzaRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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