SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eef613c7203385611db21ce2a94b7dcd54f147a406f6956bb71a555081b87aef' 
  AND token = 'sIhAV3GXFU1AsKK9AstNAyo6JCMjgWnEkl9ps3qlaTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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