SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44828087827870d5317391058a9833e9d250ccd19e4fbf6556615d2bbc061171' 
  AND token = 'ei2NsI/ss8gh+kjVKUteNDtAyDFa63bd64oqbOK/mgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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