SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52a618912fd4b591f1f5f6622dc0ac002247eadc6ac769d4bddb05fe945a9d42' 
  AND token = 'Crmi1v2UQmozpq3JrqspT97Z8YYBXG1d3JhciXFVDIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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