SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fad9bbf76dcb5595954b78c589b7ea05487d78fab66ff916b3c7c229975007fd' 
  AND token = 'hJjUjh4Iv0gHS9MV8fzl59677iPiPBhYri17aDeUUZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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