SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff19e58c18122d18b206ebae3a5258daf0180a71c2cc3b8041187ef439dbf979' 
  AND token = 'MVSBG2wv2Zsa4GLJTK9lgNJI4nIm0PMKLbxyj+UBZdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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