SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd13e793ab9cf7848ac99615e035639370e10481579b20a50358cac596a73ea7f' 
  AND token = 'nfjvkhW+rl8ah6EGqZhmDGvHVa5BlawAOAJTsNDB4xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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