SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fbd51c067e6f742dcc53f5d916da44b0084342c9f0022f1fa11efc9bde98556' 
  AND token = 'EMIV+7e+npW8HyTS3a+BRAhxP7qr1cL7WEz4bAE4mBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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