SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4236a299588b8976b01298066d794f52eaa22278d3181299b1e84c06c3c40ca' 
  AND token = 'PrmAQLbinwqKZqeKcgkMJW/B5S2xOxotmqOnef4no24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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