SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02057214b270e7a8e69b96456811089452fb8cc5b7d78468edefabed188a57a3' 
  AND token = '1oPOMlcgAEB4KcHPVecpHDkVa43FwUUdfEadqghboE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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