SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3c0e105ead7af436400899d9081bc4b2778969e6556250f1a7ebe2926f1fbd' 
  AND token = 'fCOdkUyMO2YmPnrCKozXN4Wt7lgBPpz1X1bG2tZVJ9Y=' 
  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"
    }
  }
}