SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a9e20cfa4db86d638ec9e3bc0e8934216286f416eb65427774a17e861d4b829' 
  AND token = 'cpUWV0Q2/U+BdWiiQqFOGfdrWJYRGB+4jxsJfc+xdww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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