SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec1bdf320014a1fd1cfc1a2e0cc6411b808bf2924fc896cc7cf1973ad973bc4d' 
  AND token = 'Uj4tmRlC9TuOi7ARhhvFrkjG6P8GyQE5U3E2fibblfI=' 
  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"
    }
  }
}