SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08981650531e06441d873e853e40c03c063b6551eb1acdca3a6a279d2b9faaf8' 
  AND token = 'SWzf9b8KwwWVttcZnrgZ3aORdrGAbGmjH6zA/6H8g30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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