SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f5935be42a1a846361af9da3ff695e9d01d63d18685df8b9c59ef6013d53bfd' 
  AND token = 'B/gg9aJYSZofeSsH+TM0Ee/Nzgr/7AhgUpb4Y2XZyes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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