SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be66587427e86def3d42c4c7431958b86125be6845a070c77331721eb6b57359' 
  AND token = 'xMaKT6UaK4FZ4Hh/qZpmzTVlSUX31NyP7T6mMZOE2rc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}