SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdb18eb2d1d5de57683b000c508aec06924f92cba153b662879d33efd0d23c06' 
  AND token = 'yJgvxVRTqaeIpPCvsnjoiwt74aO/zskslBTfDIWHiZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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