SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85f53ae28b67d6799f7bc9cff9d8a84d426c62105dea8511cb882937e18845fa' 
  AND token = '+uCBgX/jWtRTS8svP9AhL68NiBoNiJITHMirR7wPfmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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