SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f163c3f25716f8d1b292f0fe7928be1daf06971c8c39c63af9d051dd9b41249' 
  AND token = 'n6i7AKLLqJ0vHsMGfChg/vXXyImUqJ2IYHErAFil0vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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