SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce39add6bd34923d27aac5f34c87676e08e58f00acf745c998cef9e72c293075' 
  AND token = 'tckTBK9IA2w2PNEeZo/C+iKvMKr0o+X3k6ywfRrIiGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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