SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c726a6d9cef32e6da263749ca60ad5aa508572628447fb7d166f9899588fab48' 
  AND token = 'wCcgZxLJpQQk0Cc/9ELpTQubBPYfP8yYmwncSPz0Nfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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