SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '730fd6c41d9c6919bae70bc49ee44b9c7204cacf9be1839492543a7787cc95d9' 
  AND token = 'FhGQDF3Hl34NZHtVkuiPV+Xgn4KW3rTean6ynwEpzwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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