SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ba0cdb9e5fda02cb5e0e7579272726d0361c3cd785e41bdfa3e4c4fbf16bd6e' 
  AND token = 'c7g0QeYviaPcqDKNkcj7PVjlIVZ6WgXYdp/61DQfxzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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