SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '235d4d43abc27fb82429bc44ad517d786f9da93ee520ee7577cf1a6237c649d8' 
  AND token = 'a9nIuNciNAOvNSSxSmYo++nSPAw1IE/Lc8UtO6wti+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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