SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91481356e5afa0a383077dab90661e5b639967a3ccec96e161f3223cbfb2d885' 
  AND token = '2vBwfg+QFDGQmYug/YVEsrPNcJ9T1EPhVvf3+TIxVYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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