SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5495c308bd6d9723ffdc9d195e098c7683c282e4c9a68bfdcbbcf3d1781dd2e3' 
  AND token = 'dS3n48OlaLpRtdW2tGTAGPaTWtUyoCsAfJk9k3R1leE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}