SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00951abbbaa86ff7a7d30054ebff7858d3444889df9656b2bee112c0f33ed548' 
  AND token = '3RxiH6QbR/JeVRXaFZRnc1aeZZZaZLbdFnrQbNVuiV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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